The problem with "very much off" for font rendering is that it is relative to what you are used to, not relative to any actual standard font rendering. If you've been using Firefox a while, Chrome will look off. If you've been using Chrome, Firefox will look off.
Maybe I am reading too much into the sentence but to me, "some people just don't notice or don't care" implies that there is something objectively broken about it that can be quantified.
No, "off" in this case merely implies different from what you're used to.
This is aesthetic preference, there's no such thing as "correct". It goes back to the old debate on Mac vs. Windows font rendering -- do you like pixel alignment or do you like letterform accuracy? There's no right answer.
